Stephens stuns ailing Serena, Federer forges on

Serena Williams went down smashing rackets and screaming as she bowed out of the Australian Open quarter-finals on Wednesday, hampered by a back injury and beaten in three sets by fellow American Sloane Stephens.

The injury robbed Williams of her serve - the most effective weapon in women's tennis - but teenager Stephens will take much credit for holding her nerve to finish off the ailing 15-times grand-slam champion.

Roger Federer's bid to emulate Williams as a five-times Melbourne Park champion survived a five-set test at the hands of an inspired Jo-Wilfried Tsonga and the Swiss marched on to a last-four meeting with Andy Murray, who crushed Jeremy Chardy.

Stephens will have 24 hours to prepare for her first grand-slam semi-final against defending champion and world number one Victoria Azarenka, who came through a minor scare to beat Russian Svetlana Kuznetsova.

In Image: Sloane Stephens of the US celebrates after defeating compatriot Serena WilliamsText: Reuters